SiteImprove integration for Plone & Castle CMS was the thread where the idea was first proposed.
SiteImprove helps you improve the quality of a web site, in many measures, including accessibility compliance but also more mundane things like identifying broken links and spelling mistakes.
Wildcard Corp. has donated SiteImprove scanning of Plone.com and Plone.org so let me know if you'd like to see a copy of the report generated.